Cell Membranes Flashcards
What prevents Ions from diffusing directly through plasma membranes?
Since the phospholipid bilayer that makes up the membrane is non-polar, it only allows non-polar or uncharged particles to pass through the small openings.
Plasma membrane functions (4)
Transport, attachment, semipermeable barrier, cell communication
Passive transport
Uses energy of concentration gradient for net movement of particles from high solute concentration to low solute concentration.
Simple Diffusion
Tiny uncharged solute particles move directly through the cell membrane
Facilitated Diffusion
Large quantities of solute, large particles, or charged particles move through transporter proteins.
Osmosis
Water moves from high solvent concentration (low solute concentration) to low solvent concentration (high solute concentration)
Active transport
Uses ATP to move solutes from low concentration to high concentration via endocytosis and exocytosis. Creates or maintains a concentration gradient.
endocytosis
transport into cell via engulfing
exocytosis
transport out of cell
Primary active transport
transporter protein uses ATP to change protein shape for transport.
Secondary active transport
Using a concentration gradient of one substance, caused by primary active transport, to transport a second substance
Uniporter transporter protein
Moves one type of particle in one direction
Symporter transporter protein
Moves two types of particles in the same direction
Antiporter transporter protein
Moves two types of particles in opposite directions
Cell junctions
protein bridges that connect adjacent cells in multicellular organisms.
